Shoe insert

ABSTRACT

A shoe insert including a bladder positioned within a main body. The bladder includes a fluid tight membrane defining an interior chamber containing a liquid. The bladder further includes a heel portion in fluid communication with lateral and medial passages, which are in turn in fluid communication with a metatarsal portion. A central island of solid material is bounded by the heel portion, the lateral and medial passages, and the metatarsal portion, such that the bladder is configured to move liquid contained within the interior chamber in a cycle that conforms to a natural gait cycle.

RELATED APPLICATIONS

The present application claims priority benefits of U.S. patentapplication Ser. No. 60/565,918, entitled “Improved Shoe Insert,” whichwas filed Apr. 28, 2004, and is hereby incorporated by reference in itsentirety.

BACKGROUND OF THE INVENTION

Embodiments of the present invention generally relate to shoe inserts,and more particularly, to shoe inserts having a fluid filled bladder.

Typical shoe inserts are designed to cushion a foot during a gait cyclein order to reduce pressure on the foot. A normal gait cycle exertspressure on the heel first, then the lateral portion of the foot, andthen onto the metatarsal area of the foot. That is, when a person walks,the heel of the foot usually strikes the ground first. The naturalprogression of the gait then shifts the weight of the person from theheel area, to the lateral portion of the foot, and onto the metatarsalarea of the foot.

FIG. 1 illustrates a plan view of bones of a human foot 10 and exertionof force by the foot during a gait cycle. The foot 10 includes a medialheel area 12, a lateral heel area 14, a lateral midfoot area 16, alateral metatarsal area 18, a medial metatarsal area 20, a toe area 22,and a medial midfoot area 24. When a person walks, the weight of theperson is distributed over the plantar surface of the foot as shown byarrows A. That is, as a person walks, a supporting surface (such as afloor) is first contacted by the medial heel area 12. As the walkprogresses, contact is transferred from the medial heel area 12 to thelateral heel area 14, to the lateral midfoot area 16, onto the lateralmetatarsal area 18, to the medial metatarsal area 20, and up through thetoe area 22.

A need exists for an improved shoe insert that cushions and massages theplantar surface of the foot during the natural gait cycle.

SUMMARY OF THE INVENTION

Certain embodiments of the present invention provide a shoe insertincluding a fluid-filled central chamber, core, or bladder. The bladderincludes a robust, fluid-tight membrane that defines an interior cavity,chamber, or the like that acts as a fluid circuit or track. The interiorchamber is configured so that fluid contained therein is allowed to flowthrough the chamber. The shoe insert may be formed of solid, malleablesilicone, rubber, elastomeric, foam, or other such cushioning materials.The fluid within the bladder may be liquid silicone, such as used withbreast implants, water, saline, or various gelatinous materials mixedwith a gas, such as air.

The fluid is configured to flow within the bladder when pressure isexerted on the bladder. In general, the fluid within the bladder flowsin the exact manner in which the human foot distributes the body'sweight across the plantar (bottom) surface of the foot during a naturalgait cycle. For example, the fluid may flow in a direction from the heelto the lateral portion of the foot, through the metatarsal area of thefoot, and finally through the toes in a medial portion of the foot. Thedisplacement of fluid within the bladder of the shoe insert reducesshearing and stress forces on the foot as a person walks, and provides ashock absorbing cushion across the bottom of the foot.

Certain embodiments of the present invention provide a shoe insertconfigured to reduce the shear, stress and shock forces exerted on ahuman foot during a gait cycle. The insert includes a sealed bladderforming a chamber containing a mixture of liquid silicone and air.Optionally, the fluid may be any liquid, or semi-liquid material that iscapable of flowing within the bladder. The bladder is shaped to directlycorrespond to the weight distribution pattern of the human foot. Acentral area or island of solid material may be positioned within thebladder that separates the medial portion of the foot from the lateralportion of the foot, and the heel portion from the metatarsal head areaof the foot. The central area or island may be disposed within thebladder, or the bladder may be formed around the central area or island.Fluid flows from the heel portion, to the lateral portion, to themetatarsal head portion, to the medial portion, and back to the heelportion. The medial portion of the bladder may be expanded or widened toprovide additional arch support to the foot.

Certain embodiments of the present invention provide a shoe insert inwhich the heel portion of the bladder is circular in shape. Further, themetatarsal head area may be shaped as a semi-circle or rectangle. Thelateral and medial portions of the bladder may be elongated tubesspanning from the heel portion to the metatarsal head portion.

The shoe insert may be formed as a singular piece of material, such assolid, malleable silicone, foam, rubber, or the like, having the bladderformed therein. Optionally, the shoe insert may include a base memberintegrally formed with an upper cushioning member. The base member maybe harder than the cushioning member. For example, the base member maybe formed of solid silicone having a hardness of 50-75 durometer, whilethe cushioning member may have a hardness on the order of 10-25durometer.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a plan view of bones of a human foot and exertion offorce by the foot during a gait cycle.

FIG. 2 illustrates an isometric view of a shoe insert, according to anembodiment of the present invention.

FIG. 3 illustrates a cross-sectional view of a shoe insert along line3-3 of FIG. 2, according to an embodiment of the present invention.

FIG. 4 illustrates a plan view of a shoe insert, according to anembodiment of the present invention.

FIG. 5 illustrates a plan view of a shoe insert, according to analternative embodiment of the present invention.

FIG. 6 illustrates a plan view of a shoe insert, according to anotheralternative embodiment of the present invention.

FIG. 7 illustrates an isometric view of a heel wedge having an interiorfluid bladder, according to an embodiment of the present invention.

FIG. 8 illustrates a transverse cross-sectional view of a heel wedgealong line 8-8 shown in FIG. 7.

The foregoing summary, as well as the following detailed description ofcertain embodiments of the present invention, will be better understoodwhen read in conjunction with the appended drawings. For the purpose ofillustrating the invention, there is shown in the drawings, certainembodiments. It should be understood, however, that the presentinvention is not limited to the arrangements and instrumentalities shownin the attached drawings.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2 illustrates an isometric view of a shoe insert 26, according toan embodiment of the present invention. As shown in FIG. 2, the insert26 is foot-shaped and is configured to be inserted into a shoe. The shoeinsert 26 may be sized to fit into various size shoes. The insert 26 mayinclude a base member integrally formed with a top cushion member. Thebase member may be harder than the cushion member. For example, thehardness of the base member may be on the order of 50-75 durometer,while the hardness of the top cushion member may be on the order of10-25 durometer.

The insert 26 includes a main body 28 having a base 30 (such as the basemember discussed above), a top surface 32 (such as the top cushionmember discussed above), and outer walls 34 that are integrally formedwith the base 30 and top surface 32. A cushioning system 36 ispositioned within the main body 28. The cushioning system 36 includes abladder 38 that surrounds a solid interior area or island 40. Thebladder 38 includes a robust, fluid-tight membrane 42 that defines aninterior cavity 43, chamber, or the like that acts as a fluid circuit ortrack. The bladder 38 includes a heel portion 39 in fluid communicationwith lateral and medial passages 41 and 45, respectively. The lateraland medial passages 41 and 45 are in turn in fluid communication with ametatarsal portion 47. Thus, fluid contained within the bladder 38 maypass from the heel portion 39 to the lateral passage 41, onto themetatarsal portion 45, and returned to the heel portion 39 by way of themedial passage 45.

The interior island 40, which is bounded by the heel portion 39, thelateral and medial passages 41 and 45, and the metatarsal portion 47, isa solid piece of material that is integrally connected to the base 30and the top surface 32. The main body 28 also includes solid areas thatsurround the perimeter of the bladder 38. Namely, the main body 28includes an area defined by a medial area 44, a lateral area 46, a heelarea 48 and a toe area 50 that surrounds the outer perimeter 52 of thebladder 38.

As shown in FIG. 2, the bladder 38 does not extend to the edges of theshoe insert 26. Instead, the lateral and medial passages 41 and 45 arerecessed inwardly toward the interior island 40. For example, the medialpassage 45 may be configured to conform to the medial shape of the foot.Because a normal arch of a foot raises above the bottom surface of thefoot, the medial passage 45 may be recessed inwardly toward the island40 to accommodate the anatomical shape of the normal arch. Additionally,the metatarsal portion 47 does not extend to the tip of the insert 26.Instead, the metatarsal portion 47 may be configured to not underlie orsupport a substantial portion of the toes. Optionally, the bladder 38may extend to various areas of the shoe insert 26, including to portionsthat would substantially support the toes.

The fluid-tight membrane 42 of the bladder 38 may be formed of silicone,elastomeric materials, rubber, or any other materials that are capableof providing a fluid-tight barrier and robust enough to support theweight of a person without puncturing, tearing, or otherwise breaking.The cavity 43 defined by the fluid-tight membrane 42 contains a liquidsuch as liquid silicone, water, saline solution, or various otherliquids. The cavity 43 may not be completely filled with liquid.Instead, a portion of the cavity 43 is filled with liquid, while theremaining portion is filled with a gas, such as air, thereby allowingthe liquid contained within the cavity 43 to be displaced when a forceis exerted on the bladder 38. During a gait cycle, as described withrespect to FIG. 1, fluid is displaced within the bladder 38 as denotedby arrows C.

Alternatively, instead of a separate base member and top cushion member,the insert 26 may be formed of a single, unitary piece of materialhaving the bladders 38 formed therein. For example, the insert 26 mayinclude a single unitary main body having a uniform durometer and abladder, which may have a different durometer, formed within the mainbody.

FIG. 3 illustrates a cross-sectional view of the shoe insert 26 alongline 3-3 of FIG. 2, according to an embodiment of the present invention.As shown in FIG. 3, the metatarsal portion 47 is thinner than the heelportion 39. In particular, the shape of the shoe insert 26, and thebladder 38, tapers down from the heel portion 39 to the metatarsalportion 47.

FIG. 4 illustrates a plan view of the shoe insert 26. During a gaitcycle, when the heel hits the ground, fluid is displaced from the heelportion 39 into the lateral passage 41, thereby supporting the heel andlateral portion of the foot as those portions of the foot support theweight of the person (i.e., as those portions of the foot are proximatethe ground). As the gait progresses such that the metatarsals supportthe weight of the body, fluid is displaced from the lateral passage 41to the metatarsal portion 47 of the bladder 38. As the shoe leavescontact with the ground, the fluid is passed from the metatarsal portion47 back to the heel portion 39 by way of the medial passage 45. Ingeneral, as force, such as the weight of person, is exerted on thebladder 38 through a person's foot, a fluid cycle is produced in thedirection of arrows C, which corresponds to, and follows, the gait cycle(as shown in FIG. 1) of a human foot during a natural gait or walk.

FIG. 5 illustrates a plan view of a shoe insert 54, according to analternative embodiment of the present invention. As shown in FIG. 5, thebladder 55 occupies more space within the insert 54.

FIG. 6 illustrates a plan view of a shoe insert 56, according to anotheralternative embodiment of the present invention. As shown in FIG. 6, theinsert 56 includes a bladder 57 having an expanded medial portion 59configured to provide additional arch support.

FIG. 7 illustrates an isometric view of a heel wedge 60 having aninterior fluid bladder 62, according to an embodiment of the presentinvention.

FIG. 8 illustrates a transverse cross-sectional view of the heel wedge60 along line 8-8 shown in FIG. 7.

As discussed above and shown in the drawings, embodiments of the presentinvention provide an improved shoe insert that cushions and massages theplantar surface of the foot during the natural gait cycle. Theembodiments of the present invention also provide a simple shoe inserthaving a fluid bladder that is devoid of valves, throttles, distinctfluid regulators, and the like.

While the invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the invention without departing from its scope.Therefore, it is intended that the invention not be limited to theparticular embodiments disclosed, but that the invention will includeall embodiments falling within the scope of the appended claims.

1. A shoe insert configured to cushion a foot through a normal gaitcycle comprising: a main body formed of a solid material configured tosupport and cushion a foot, said main body being defined by an outerperimeter that bounds a heel area, a lateral area, a medial area, and atoe area; and a bladder positioned within said main body, said bladderincluding a fluid tight membrane defining an interior chamber containinga fluid, said interior chamber being defined by a heel portion in fluidcommunication with lateral and medial passages, which are in turn influid communication with a metatarsal portion, wherein a central islandof solid material is bounded by said heel portion, said lateral andmedial passages, and said metatarsal portion, wherein said bladder isconfigured to move said fluid contained within said interior chamber ina cycle that conforms to the natural gait cycle.
 2. The shoe insert ofclaim 1, wherein said fluid moves from said heel portion to said lateralpassage during the natural gait cycle, wherein said fluid passes fromsaid lateral passage onto said metatarsal portion during the naturalgait cycle, and wherein said fluid is returned to said heel portion byway of said medial passage during the natural gait cycle.
 3. The shoeinsert of claim 1, wherein said fluid moves within said interior chamberin an exact manner in which a human foot distributes weight across aplantar surface of the foot during the natural gait cycle.
 4. The shoeinsert of claim 1, wherein said fluid is a mixture of liquid siliconeand air.
 5. The shoe insert of claim 1, wherein said main body includesa base secured to an upper cushion.
 6. The shoe insert of claim 5,wherein said base is formed of solid silicone having a hardness on theorder of 50-75 durometer.
 7. The shoe insert of claim 5, wherein saidupper cushion is formed of solid silicone having a hardness on the orderof 10-25 durometer.
 8. The shoe insert of claim 1, wherein at least oneof said heel portion, said lateral and medial passages, and saidmetatarsal portion are recessed away from said outer perimeter towardsaid central island.
 9. A shoe insert configured to cushion a footthrough a normal gait cycle comprising: a main body formed of a solidmaterial configured to support and cushion a foot, said main body beingdefined by an outer perimeter that bounds a heel area, a lateral area, amedial area, and a toe area; and a fluid-tight bladder containing afluid supported by said main body, wherein said fluid is a mixture ofliquid silicone and air, said bladder comprising a heel portion in fluidcommunication with lateral and medial passages, said lateral and medialportions also being in fluid communication with a metatarsal portion,wherein a central island of solid material is bounded by said heelportion, said lateral and medial passages, and said metatarsal portion,wherein said bladder is configured to move said fluid in a cycle thatconforms to the exact manner in which a human foot distributes weightacross a plantar surface of the foot during the natural gait cycle. 10.The shoe insert of claim 9, wherein said fluid moves from said heelportion to said lateral passage during the natural gait cycle, whereinsaid fluid passes from said lateral passage onto said metatarsal portionduring the natural gait cycle, and wherein said fluid is returned tosaid heel portion by way of said medial passage during the natural gaitcycle.
 11. The shoe insert of claim 9, wherein said main body includes abase secured to an upper cushion.
 12. The shoe insert of claim 11,wherein said base is formed of solid silicone having a hardness on theorder of 50-75 durometer.
 13. The shoe insert of claim 11, wherein saidupper cushion is formed of solid silicone having a hardness on the orderof 10-25 durometer.
 14. The shoe insert of claim 9, wherein at least oneof said heel portion, said lateral and medial passages, and saidmetatarsal portion are recessed toward said central island.
 15. A shoeinsert configured to cushion a foot through a normal gait cyclecomprising: a main body formed of a solid material configured to supportand cushion a foot, said main body being defined by an outer perimeterthat bounds a heel area, a lateral area, a medial area, and a toe area;and a fluid-tight bladder containing a fluid supported by said mainbody, said bladder comprising a heel portion in fluid communication withlateral and medial passages, said lateral and medial portions also beingin fluid communication with a metatarsal portion, wherein a centralisland of solid material is bounded by said heel portion, said lateraland medial passages, and said metatarsal portion, at least one of saidheel portion, said lateral and medial passages, and said metatarsalportion being recessed away from said outer perimeter and toward saidcentral island, wherein said bladder is configured to move said fluid ina cycle that conforms to the exact manner in which a human footdistributes weight across a plantar surface of the foot during thenatural gait cycle, wherein said fluid moves from said heel portion tosaid lateral passage during the natural gait cycle, wherein said fluidpasses from said lateral passage onto said metatarsal portion during thenatural gait cycle, and wherein said fluid is returned to said heelportion by way of said medial passage during the natural gait cycle. 16.The shoe insert of claim 15, wherein said main body includes a basesecured to an upper cushion.
 17. The shoe insert of claim 16, whereinsaid base is formed of solid silicone having a hardness on the order of50-75 durometer.
 18. The shoe insert of claim 17, wherein said uppercushion is formed of solid silicone having a hardness on the order of10-25 durometer.
 19. The shoe insert of claim 15, wherein the shoeinsert is devoid of any valves.